A SELECTION PROCEDURE FOR ENHANCING THE EXPRESSION OF MALIGNANT TRANSFORMATION IN PRIMARY SYRIAN HAMSTER EMBRYO CELLS.

THE PURPOSE OF THIS PROJECT IS TO IMPROVE THE HAMSTER EMBRYO CELL CLONAL TRANSFORMATION ASSAY TO INCREASE THE MORPHOLOGICAL TRANSFORMATION RATE AND INTRODUCE AN ADDITIONAL ENDPOINT, COLONY FORMATION IN SOFT AGAROSE. THE METHODOLOGY DESCRIBED INTRODUCES A SELECTIVE STEP WHICH ENTAILS SUSPENSION OF CHEMICALLY-TREATED AND CONTROL CELLS IN LIQUID MEDIUM OVER A SOLID AGAR BASE FOR UP TO FOUR DAYS,FOLLOWED BY RESEEDING INTO MONOLAYER CULTURE AND GROWTH TO CONFLUENCE. THE SELECTIVE STEP MAY BE REPEATED IF NECESSARY. CELLS ARE THEN SEEDED AT LOW NUMBERS IN 60 MM PETRI DISHES TO SCORE FOR ALTERED COLONIES, PLATED IN SOFT AGAROSE OR SUBCULTURED INTO FLASKS AT HIGH DENSITY. DURING PHASE I THE NUMBER OF DAYS IN SUSPENSION WOULD BE VARIED TO MAXIMIZE REDUCTION IN NORMAL CELL NUMBERS UTILIZING ONE OR TWO KNOWN CARCINOGENIC CHEMICALS. IN PHASE II ADDITIONAL CHEMICALS WOULD BE EXAMINED, INCLUDING CARCINOGENS, NONCARCINOGENS AND CHEMICALS POSSIBLY REQUIRING METABOLIC ACTIVATION, TO VALIDATE THE SYSTEM. IN ADDITION THE APPLICATION OF MOLECULAR ENDPOINTS (E.G. ONCOGENE ENDPOINTS)WILL BE INVESTIGATED. THE COMMERCIAL APPLICATION OF THIS WORK IS THE USE OF A SCREENING SYSTEM FOR THE IDENTIFICATIONOF CARCINOGENS WHICH IS MORE OBJECTIVE THAN THOSE CURRENTLY IN USE AND MORE CLOSELY ASSOCIATED WITH TUMORIGENICITY.